Signaling molecules such as neurotrophins, neuropeptides, axon guidance molecules and neurotransmitters are traditionally associated with nervous system function have also been implicated in cancer and may play an important role in promoting cancer outgrowth and expansion by mediating the reciprocal cross-talk between nerves and cancer cells, particularly in the context of the tumor microenvironment6–8. The gene discussed is BDNF; the disease is cancer.